CN104283226B - A kind of photovoltaic plant group based on energy storage sends transmission line capability static optimization method outside - Google Patents

Abstract

The present invention relates to a kind of photovoltaic plant group based on energy storage and send transmission line capability static optimization method outside, for the outer power transmission capacity unreasonable allocation of current photovoltaic plant group, problem that utilization rate is lower, the present invention is taking the meritorious power producing characteristics of photovoltaic plant and part throttle characteristics as basis, consider transmission of electricity income, transmission line construction cost, energy-storage system cost, reduce the factors such as spare capacity and ambient influnence, set up the majorized function that turns to target with transmission system comprehensive method of investment Income Maximum, optimized photovoltaic plant with this and send transmission line capability outside. The advantages such as have methodological science reasonable, applicability is strong, comprehensive income maximization.

Description

A kind of photovoltaic plant group based on energy storage sends transmission line capability static optimization method outside

Technical field

The present invention relates to a kind of photovoltaic plant group based on energy storage and send transmission line capability static optimization method outside.

Background technology

Along with economic fast development, make the immense pressure of people's while facing to energy and environment. Solar energy can be again as oneThe raw energy, has the features such as safe, clean, widely distributed, more and more receives people's concern. Large-scale centralized photovoltaicGrid-connected system is one of development trend of solar electrical energy generation, and it is mostly distributed in solar energy resources and relatively enriches stable remoteArea, away from load center, by high voltage, remote transmission line of electricity connecting system.

Solar energy is different from other regenerative resources such as wind energy, water energy, has its unique natural characteristic. The generated energy of photovoltaic plant withIntensity of solar radiation, temperature are closely related. Post sunset, solar cell cannot generate electricity at night. Because blocking, cloud layer causes tooThe uncertainty of sun radiation, the protection action of photovoltaic plant, and solar panel hot spot effect, the factor such as aging, photovoltaicMeritorious the exerting oneself in power station is difficult to reach its peak power; Meanwhile, for above-mentioned reasons produce meritorious go out fluctuation, along with photovoltaicThe expansion of installed capacity of power station, is also difficult to ignore on the impact of grid stability. Although energy-storage system cost is higher, can be realShow the space-time translation of energy, meet the active balance of system. For planning to build the large-scale photovoltaic plant group who establishes, can be by increasingEnergy-storage system improves photovoltaic plant group power producing characteristics.

Conventional photovoltaic station group transmission system is, by circuit, each photovoltaic plant power is pooled to a Central Substations, more logicalCross the transmission line of electricity access electrical network that one or more rounds electric pressure is higher, transmission line of electricity capacity collocation method is the dress by photovoltaic plantMachine capacity configures. For the western China with large-scale photovoltaic generating access electrical network, annual interest is completely sent out in photovoltaic generation equivalenceBe about 1600 hours with hourage. If according to installed capacity configuration transmission line of electricity capacity, this will cause transmission line of electricity to utilize waterFlat lower; If reduce transmission line of electricity capacity, probably cause in photovoltaic generation peak period, power can not be sent in time, leadsCausing " abandoning light rations the power supply " phenomenon occurs.

For large-sized photovoltaic station group, photovoltaic plant construction investment is large, but the transformation efficiency of solar energy is not high. Photovoltaic plant groupSend transmission line capability configuration outside, not only will treasure valuable solar electrical energy generation resource, also will reduce as much as possible photovoltaic power generation grid-connecting pairThe impact that electrical network causes. Therefore, be necessary to consider many-sided factor, optimize transmission line construction scheme, improve transmission systemComprehensive income.

Summary of the invention

Technical problem to be solved by this invention is, propose a kind of taking the meritorious power producing characteristics of photovoltaic plant and part throttle characteristics as basis,Consider transmission of electricity income, transmission line construction cost, energy-storage system cost, reduce the factors such as spare capacity and ambient influnence,Set up the majorized function that turns to target with transmission system comprehensive method of investment Income Maximum, optimized photovoltaic plant with this and send transmission of electricity appearance outsideThe photovoltaic plant group based on energy storage of amount sends transmission line capability static optimization method outside.

The scheme that solves its technical problem employing is: a kind of photovoltaic plant group based on energy storage sends transmission line capability static optimization method outside,It comprises the following steps:

1) photovoltaic plant group power producing characteristics is analyzed

Large-scale photovoltaic plant group is made up of multiple photovoltaic plants conventionally, and meritorious the exerting oneself of each photovoltaic plant arrived by line convergenceA Bulk Supply Substation, then by one time or many back transmission lines access electrical network, the solar panel institute of different installed positionsThe situation at place is often different, causes the photovoltaic battery panel power output difference in diverse location or region; Meanwhile, photovoltaic plant and lightBetween overhead utility, power output is also incomplete same, along with photovoltaic plant group's scale constantly expands, photovoltaic is meritorious exert oneself maximum withAfter total installation of generating capacity standardization, its value reduces gradually, reflects that by photovoltaic plant accumulation power curve photovoltaic plant group scale expandsPower changing rule after large, can serve as the foundation of optimizing transmission line capability;

2) in conjunction with the photovoltaic generating system Analysis of Peak Regulation Capability of energy-storage system

The object of peak regulation reduce as far as possible high-power load in period on power load peak the demand to electric energy, it shows intuitivelyFor reducing the peak-valley difference of load; Transmission system in conjunction with energy-storage system can reduce part transmission line capability, by energy storage, photovoltaic is sent outThe electricity electrical power storage that transmission line of electricity cannot be sent when peak, discharged in the time of peak of power consumption, reduced transmission line of electricityCost has improved the power peak of electrical network simultaneously, plays Peak Load Adjustment, ensures the reliability of power supply;

3) send transmission line capability optimization outside based on energy storage

Based on the meritorious power producing characteristics of photovoltaic plant and energy-storage system as reducing transmission line of electricity capacity, regulate the work of load peak-valley differenceWith, consider transmission line construction cost, transmission of electricity income, the peak regulation cost reducing and environment income simultaneously, build reflection defeatedThe transmission line capability majorized function of electrical engineering comprehensive income:

$\underset{0\≤P_{\mathrm{line}}\≤P_N}{\max }F=R\left(P_{\mathrm{line}}\right)+S\left(P_{\mathrm{line}}\right)+T\left(P_{\mathrm{line}}\right)+E\left(P_{\mathrm{line}}\right)-C\left(P_{\mathrm{line}}\right)-\mathrm{SC}\left(P_{\mathrm{line}}\right)---\left(1\right)$

In formula: F is that photovoltaic generation is sent power transmission engineering comprehensive income outside;

P_lineFor photovoltaic generation is sent transmission line capability outside, P_NFor photovoltaic plant group total installation of generating capacity;

Every implication and the computational methods in equation right side are as follows in formula (1):

①R(P_line)

R(P_line) be transmission system direct yield, be directly proportional to trnamission capacity, its computing formula is:

R(P_line)＝r_t×G_t(P_line)×T_s(2)

Wherein: r_tConvey unit electric weight income;

T_sFor transmitting electricity static return period;

G_t(P_line) be the annual electric weight of directly carrying by transmission line of electricity, ask method as follows:

$G_t\left(P_{\mathrm{line}}\right)=P_{\mathrm{line}}\×T_{\mathrm{line}}+{\∫}_{T_{\mathrm{line}}}^{T_{\mathrm{end}}}{P}_s\left(t\right)\mathrm{dt}---\left(3\right)$

Wherein: T_lineFor photovoltaic plant group power output is higher than P_lineThe continuous output time;

T_endFor total the exerting oneself the time of photovoltaic plant group;

P_s(t) be photovoltaic plant group accumulation power curve;

②S(P_line)

S(P_line) be energy-storage system storage of electrical energy transmission of electricity income, its computing formula is:

S(P_line)＝η×r_t×G_s(P_line)×T_s(4)

Wherein: η is energy-storage system efficiency;

G_s(P_line) be energy-storage system storage of electrical energy, its computing formula is:

$G_s\left(P_{\mathrm{line}}\right)={\∫}_0^{T_{\mathrm{line}}}{P}_s\left(t\right)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}}---\left(5\right)$

③T(P_line)

T(P_line) for reducing peak income, its computing formula is:

T(P_line)＝365×k×P_maxs(P_line)×T_s(6)

Wherein: k unit power peak regulation cost;

P_maxs(P_line) be the peak power of energy-storage system, ask method as follows:

P_maxs(P_line)＝max(P_s(t))-P_line(7)

④E(P_line)

E(P_line) reduce traditional energy consumption and the Environmental costs of bringing, the electric energy that transmission line of electricity fails to send is not abandonedFall, but utilize the remaining ability to transmit electricity of transmission line of electricity that this part electric energy is sent rush hour at generating low ebb or load, itsComputing formula is:

E(P_line)＝(r_c+r_e)×G_s(P_line)×T_s(8)

Wherein: r_cFor consuming traditional energy fuel used to generate electricity cost;

r_eFor its Environmental costs of bringing;

⑤C(P_line)

C(P_line) be transmission line construction cost, ask method as follows:

C(P_line)＝r_l×l×P_line(9)

Wherein: r_lFor unit length transmission line construction cost;

L is transmission line length;

⑥SC(P_line)

SC(P_line) be energy-storage system construction cost, ask method as follows:

$\mathrm{SC}\left(P_{\mathrm{line}}\right)=(r_{\mathrm{sp}}\×P_{\max s}\left(P_{\mathrm{line}}\right)+r_{\mathrm{se}}\×E_s\left(P_{\mathrm{line}}\right))\×\frac{T_s}{T_d}---\left(10\right)$

Wherein: r_spFor energy-storage system unit power cost;

r_seFor energy-storage system unit energy cost;

T_dFor energy-storage system life cycle;

E_s(P_line) be energy storage system capacity, because energy-storage system cost is higher, configure jumbo energy-storage system unrealistic,Energy-storage system desired volume only need calculate stored electric energy every day, and gets its maximum, and its computational methods are as follows:

$E_s\left(P_{\mathrm{line}}\right)=\max (\underset{0}{\overset{T_{\mathrm{line}}\left(N\right)}{\∫}}{P}_{\mathrm{sd}}(t,N)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}}\left(N\right))---\left(11\right)$

Wherein: N is number of days, get 1,2,3 ..., 365;

P_sd(t, N) is N days photovoltaic plant group accumulation power curves;

T_line(N) be that N days photovoltaic plant group power outputs are higher than P_lineThe continuous output time;

(1) the optimal solution P of formula object function_lineBe and make the maximized transmission line capability of comprehensive income, by P_line(7) formula of determiningAnd (11) formula, i.e. required energy-storage system power and capacity.

A kind of photovoltaic plant group based on energy storage of the present invention sends transmission line capability static optimization method outside, exerts oneself so that photovoltaic plant is meritoriousCharacteristic and part throttle characteristics be basis, consider transmission of electricity income, transmission line construction cost, energy-storage system cost, reduce for subsequent useThe factor such as capacity and ambient influnence, has set up the majorized function that turns to target with transmission system comprehensive method of investment Income Maximum, comes with thisThe advantages such as optimization photovoltaic plant is sent transmission line capability outside, has methodological science reasonable, and applicability is strong, comprehensive income maximization.

Brief description of the drawings

Fig. 1 is different weather situation photovoltaic plant group power curve comparison diagram;

Fig. 2 is photovoltaic generation accumulation power curve schematic diagram;

Fig. 3 is photovoltaic plant group daily output curve after configuration energy storage, load curve and net load curve map;

Fig. 4 is that Computing Principle of the present invention is analyzed schematic diagram;

Fig. 5 is the optimum transmission line capability schematic diagram of photovoltaic plant group of the present invention.

Detailed description of the invention

Utilize drawings and Examples to send transmission line capability static optimization method outside to a kind of photovoltaic plant group based on energy storage of the present invention belowBe described further.

A kind of photovoltaic plant group based on energy storage of the present invention sends transmission line capability static optimization method outside, comprises the following steps:

1) photovoltaic plant group power producing characteristics is analyzed

Large-scale photovoltaic plant group is made up of multiple photovoltaic plants conventionally, and meritorious the exerting oneself of each photovoltaic plant arrived by line convergenceA Bulk Supply Substation, then by one time or many back transmission lines access electrical network, the solar panel institute of different installed positionsThe situation at place is often different, causes the photovoltaic battery panel power output difference in diverse location or region; Meanwhile, photovoltaic plant and lightBetween overhead utility, power output is also incomplete same, along with photovoltaic plant group's scale constantly expands, photovoltaic is meritorious exert oneself maximum withAfter total installation of generating capacity standardization, its value reduces gradually, reflects that by photovoltaic plant accumulation power curve photovoltaic plant group scale expandsPower changing rule after large, can serve as the foundation of optimizing transmission line capability;

2) in conjunction with the photovoltaic generating system Analysis of Peak Regulation Capability of energy-storage system

The object of peak regulation reduce as far as possible high-power load in period on power load peak the demand to electric energy, it shows intuitivelyFor reducing the peak-valley difference of load; Transmission system in conjunction with energy-storage system can reduce part transmission line capability, by energy storage, photovoltaic is sent outThe electricity electrical power storage that transmission line of electricity cannot be sent when peak, discharged in the time of peak of power consumption, reduced transmission line of electricityCost has improved the power peak of electrical network simultaneously, plays Peak Load Adjustment, ensures the reliability of power supply;

3) send transmission line capability optimization outside based on energy storage

Based on the meritorious power producing characteristics of photovoltaic plant and energy-storage system as reducing transmission line of electricity capacity, regulate the work of load peak-valley differenceWith, consider transmission line construction cost, transmission of electricity income, the peak regulation cost reducing and environment income simultaneously, build reflection defeatedThe transmission line capability majorized function of electrical engineering comprehensive income:

$\underset{0\≤P_{\mathrm{line}}\≤P_N}{\max }F=R\left(P_{\mathrm{line}}\right)+S\left(P_{\mathrm{line}}\right)+T\left(P_{\mathrm{line}}\right)+E\left(P_{\mathrm{line}}\right)-C\left(P_{\mathrm{line}}\right)-\mathrm{SC}\left(P_{\mathrm{line}}\right)---\left(1\right)$

In formula: F is that photovoltaic generation is sent power transmission engineering comprehensive income outside;

P_lineFor photovoltaic generation is sent transmission line capability outside, P_NFor photovoltaic plant group total installation of generating capacity;

Every implication and the computational methods in equation right side are as follows in formula (1):

⑦R(P_line)

R(P_line) be transmission system direct yield, be directly proportional to trnamission capacity, its computing formula is:

R(P_line)＝r_t×G_t(P_line)×T_s(2)

Wherein: r_tConvey unit electric weight income;

T_sFor transmitting electricity static return period;

G_t(P_line) be the annual electric weight of directly carrying by transmission line of electricity, ask method as follows:

$G_t\left(P_{\mathrm{line}}\right)=P_{\mathrm{line}}\×T_{\mathrm{line}}+{\∫}_{T_{\mathrm{line}}}^{T_{\mathrm{end}}}{P}_s\left(t\right)\mathrm{dt}---\left(3\right)$

Wherein: T_lineFor photovoltaic plant group power output is higher than P_lineThe continuous output time;

T_endFor total the exerting oneself the time of photovoltaic plant group;

P_s(t) be photovoltaic plant group accumulation power curve;

⑧S(P_line)

S(P_line) be energy-storage system storage of electrical energy transmission of electricity income, its computing formula is:

S(P_line)＝η×r_t×G_s(P_line)×T_s(4)

Wherein: η is energy-storage system efficiency;

G_s(P_line) be energy-storage system storage of electrical energy, its computing formula is:

$G_s\left(P_{\mathrm{line}}\right)={\∫}_0^{T_{\mathrm{line}}}{P}_s\left(t\right)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}}---\left(5\right)$

⑨T(P_line)

T(P_line) for reducing peak income, its computing formula is:

T(P_line)＝365×k×P_maxs(P_line)×T_s(6)

Wherein: k unit power peak regulation cost;

P_maxs(P_line) be the peak power of energy-storage system, ask method as follows:

P_maxs(P_line)＝max(P_s(t))-P_line(7)

⑩E(P_line)

E(P_line) reduce traditional energy consumption and the Environmental costs of bringing, the electric energy that transmission line of electricity fails to send is not abandonedFall, but utilize the remaining ability to transmit electricity of transmission line of electricity that this part electric energy is sent rush hour at generating low ebb or load, itsComputing formula is:

E(P_line)＝(r_c+r_e)×G_s(P_line)×T_s(8)

Wherein: r_cFor consuming traditional energy fuel used to generate electricity cost;

r_eFor its Environmental costs of bringing;

C(P_line)

C(P_line) be transmission line construction cost, ask method as follows:

C(P_line)＝r_l×l×P_line(9)

Wherein: r_lFor unit length transmission line construction cost;

L is transmission line length;

SC(P_line)

SC(P_line) be energy-storage system construction cost, ask method as follows:

$\mathrm{SC}\left(P_{\mathrm{line}}\right)=(r_{\mathrm{sp}}\×P_{\max s}\left(P_{\mathrm{line}}\right)+r_{\mathrm{se}}\×E_s\left(P_{\mathrm{line}}\right))\×\frac{T_s}{T_d}---\left(10\right)$

Wherein: r_spFor energy-storage system unit power cost;

r_seFor energy-storage system unit energy cost;

T_dFor energy-storage system life cycle;

E_s(P_line) be energy storage system capacity, because energy-storage system cost is higher, configure jumbo energy-storage system unrealistic,Energy-storage system desired volume only need calculate stored electric energy every day, and gets its maximum, and its computational methods are as follows:

$E_s\left(P_{\mathrm{line}}\right)=\max (\underset{0}{\overset{T_{\mathrm{line}}\left(N\right)}{\∫}}{P}_{\mathrm{sd}}(t,N)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}}\left(N\right))---\left(11\right)$

Wherein: N is number of days, get 1,2,3 ..., 365;

P_sd(t, N) is N days photovoltaic plant group accumulation power curves;

T_line(N) be that N days photovoltaic plant group power outputs are higher than P_lineThe continuous output time;

(1) the optimal solution P of formula object function_lineBe and make the maximized transmission line capability of comprehensive income, by P_line(7) formula of determiningAnd (11) formula, i.e. required energy-storage system power and capacity.

Specific embodiments of the invention are: to NORTHWEST CHINA large-sized photovoltaic station group, total installation of generating capacity 350MW sends 100km outsideWork transmission line carries out transmission line capability optimal design, and data are from photovoltaic plant group measured data, and the acquisition of data can adopt abilityThe familiar commercially available prod data acquisition unit of field technique personnel is realized.

Embodiment design conditions are described as follows:

1) convey unit electric weight income r_t=0.06 yuan/kWh,

2) transmission of electricity static return period of T_s=20 years,

3) energy-storage system efficiency eta=0.9,

4) unit power peak regulation cost k=0.115 unit/kW,

5) consume traditional energy fuel used to generate electricity cost r_c=0.328 yuan/kWh,

6) consume the traditional energy Environmental costs r bringing that generates electricity_e=0.109 yuan/kWh,

7) unit length transmission line construction cost r_l=100 ten thousand yuan/(MW100km),

8) energy-storage system unit power cost r_sp=3600 yuan/kW,

9) energy-storage system unit energy cost r_se=900 yuan/kWh,

10) energy-storage system life cycle T_d=10 years.

Under above-mentioned design conditions, application the inventive method sends to embodiment photovoltaic plant group power the result that transmission line capability is optimized outsideAs follows:

1. photovoltaic plant group power producing characteristics is analyzed

In embodiment, as shown in Figure 1, photovoltaic plant group year is accumulated the song of exerting oneself to photovoltaic plant group different weather sequential power producing characteristics curveLine as shown in Figure 2. Fig. 1 show photovoltaic plant group meritorious exert oneself closely related with weather conditions, even but weather conditions are goodSituation under meritorious the exerting oneself of photovoltaic plant be difficult to reach its peak power. Fig. 2 shows, exerts oneself large in 1 year 8760 hoursOnly have 4400 hours in zero time.

2. in conjunction with the photovoltaic generating system Analysis of Peak Regulation Capability of energy-storage system

As shown in Figure 3, load peak appears at about 16 o'clock substantially, and the peak of photovoltaic generation is due to the difference in geographical positionAnd different, in case study on implementation, photovoltaic power station power generation peak is after 12 o'clock. In conjunction with the sunrise of the photovoltaic generating system after energy-storage systemForce curve, the effect of its peak load shifting is comparatively obvious, and system peak-valley difference is reduced to original 95%.

3. send transmission line capability optimization method outside based on energy storage

Bring design conditions into formula (1)-(11), obtain the present embodiment wind farm group and send transmission line capability optimization aim function outsideConcrete form, is represented by formula (12)-(18):

$\underset{0\≤P_{\mathrm{line}}\≤P_N}{\max }F=R\left(P_{\mathrm{line}}\right)+S\left(P_{\mathrm{line}}\right)+T\left(P_{\mathrm{line}}\right)+E\left(P_{\mathrm{line}}\right)-C\left(P_{\mathrm{line}}\right)-\mathrm{SC}\left(P_{\mathrm{line}}\right)---\left(12\right)$

Wherein: $R\left(P_{\mathrm{line}}\right)=0.06\×(P_{\mathrm{line}}\×T_{\mathrm{line}}+{\∫}_{T_{\mathrm{line}}}^{T_{\mathrm{end}}}{P}_s\left(t\right)\mathrm{dt})\×20---\left(13\right)$

$S\left(P_{\mathrm{line}}\right)=0.9\×0.06\×({\∫}_0^{T_{\mathrm{line}}}{P}_s\left(t\right)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}})\×20---\left(14\right)$

T(P_line)＝365×0.115×(max(P_s(t))-P_line)×20(15)

$E\left(P_{\mathrm{line}}\right)=(0.109+0.328)\×({\∫}_0^{T_{\mathrm{line}}}{P}_s\left(t\right)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}})\×20---\left(16\right)$

C(P_line)＝100×10⁴×100×P_line/10³(17)

$\begin{array}{c}\mathrm{SC}\left(P_{\mathrm{line}}\right)=(3600\×\max \left(P_s\left(t\right)\right)-P_{\mathrm{line}})+900\×\left(\max \right(\\ \underset{0}{\overset{T_{\mathrm{line}}\left(N\right)}{\∫}}{P}_{\mathrm{sd}}(t,N)\mathrm{dt}-P_{\mathrm{line}}\×T_{\mathrm{line}}\left(N\right)))\×\frac{20}{10}\end{array}---\left(18\right)$

Above each result of calculation unit: unit;

Fig. 4 is that the know-why of the inventive method is analyzed schematic diagram, and in figure, dark part represents that current photovoltaic sends transmission line capability outside and beP_lineTime the electric weight that can send. Light-colored part is that photovoltaic power station power generation power is greater than P_lineTime energy-storage system storage electric weight. ImproveP_lineCan reduce energy-storage system consumption, but transmission system cost can raise; Reduce P_lineCan reduce transmission system cost, but storageCan system cost can increase.

Can obtain according to above-mentioned majorized function, transmission system capacity is 272MW, and energy-storage system power is 339kW, and capacity isWhen 84kWh, power transmission engineering total revenue maximum, reaches 3.12 hundred million yuan. If defeated according to photovoltaic plant group installed capacity 350MW configurationCapacitance, comprehensive income is only 2.36 hundred million yuan, is less than this method income, as shown in Figure 5.

Design conditions, legend etc. in the embodiment of the present invention be only for the present invention is further illustrated, and non exhaustive, noForm the restriction to claim protection domain, the enlightenment that those skilled in the art obtain according to the embodiment of the present invention, without woundIt is alternative that the property made work just can expect that other is equal in fact, all in protection domain of the present invention.

Claims (1)

1. the photovoltaic plant group based on energy storage sends a transmission line capability static optimization method outside, it is characterized in that, it comprises the following steps:

1) photovoltaic plant group power producing characteristics is analyzed

Large-scale photovoltaic plant group is made up of multiple photovoltaic plants conventionally, and meritorious the exerting oneself of each photovoltaic plant arrived by line convergenceA Bulk Supply Substation, then by one time or many back transmission lines access electrical network, the photovoltaic battery panel of different installed positions is of living inSituation often different, cause the photovoltaic battery panel power output difference in diverse location or region; Meanwhile, photovoltaic plant and photovoltaicBetween power station, power output is also incomplete same, and along with photovoltaic plant group's scale constantly expands, photovoltaic is meritorious exerts oneself maximum with alwaysAfter installed capacity standardization, its value reduces gradually, reflects photovoltaic plant group popularization by photovoltaic plant accumulation power curveAfter power changing rule, can serve as the foundation of optimizing transmission line capability;

2) in conjunction with the photovoltaic generating system Analysis of Peak Regulation Capability of energy-storage system

The object of peak regulation reduce as far as possible high-power load in period on power load peak the demand to electric energy, it shows intuitivelyFor reducing the peak-valley difference of load; Transmission system in conjunction with energy-storage system can reduce part transmission line capability, by energy storage, photovoltaic is sent outThe electricity electrical power storage that transmission line of electricity cannot be sent when peak, discharged in the time of peak of power consumption, reduced transmission line of electricityCost has improved the power peak of electrical network simultaneously, plays Peak Load Adjustment, ensures the reliability of power supply;

3) send transmission line capability optimization outside based on energy storage

Based on the meritorious power producing characteristics of photovoltaic plant and energy-storage system as reducing transmission line of electricity capacity, regulate the work of load peak-valley differenceWith, consider transmission line construction cost, transmission of electricity income, the peak regulation cost reducing and environment income simultaneously, build reflection defeatedThe transmission line capability majorized function of electrical engineering comprehensive income:

$\underset{0\≤P_{line}\≤P_N}{\max }F=R\left(P_{line}\right)+S\left(P_{line}\right)+T\left(P_{line}\right)+E\left(P_{line}\right)-C\left(P_{line}\right)-SC\left(P_{line}\right)---\left(1\right)$

In formula: F is that photovoltaic generation is sent power transmission engineering comprehensive income outside;

P_lineFor photovoltaic generation is sent transmission line capability outside, P_NFor photovoltaic plant group total installation of generating capacity;

Every implication and the computational methods in equation right side are as follows in formula (1):

①R(P_line)

R(P_line) be transmission system direct yield, be directly proportional to trnamission capacity, its computing formula is:

R(P_line)＝r_t×G_t(P_line)×T_s(2)

Wherein: r_tConvey unit electric weight income;

T_sFor transmitting electricity static return period;

G_t(P_line) be the annual electric weight of directly carrying by transmission line of electricity, ask method as follows:

$G_t\left(P_{line}\right)=P_{line}\×T_{line}+{\∫}_{T_{line}}^{T_{end}}{P}_s\left(t\right)dt---\left(3\right)$

Wherein: T_lineFor photovoltaic plant group power output is higher than P_lineThe continuous output time;

T_endFor total the exerting oneself the time of photovoltaic plant group;

P_s(t) be photovoltaic plant group accumulation power curve;

②S(P_line)

S(P_line) be energy-storage system storage of electrical energy transmission of electricity income, its computing formula is:

S(P_line)＝η×r_t×G_s(P_line)×T_s(4)

Wherein: η is energy-storage system efficiency;

G_s(P_line) be energy-storage system storage of electrical energy, its computing formula is:

$G_s\left(P_{line}\right)={\∫}_0^{T_{line}}{P}_s\left(t\right)dt-P_{line}\×T_{line}---\left(5\right)$

③T(P_line)

T(P_line) for reducing peak income, its computing formula is:

T(P_line)＝365×k×P_maxs(P_line)×T_s(6)

Wherein: k unit power peak regulation cost;

P_maxs(P_line) be the peak power of energy-storage system, ask method as follows:

P_maxs(P_line)＝max(P_s(t))-P_line(7)

④E(P_line)

E(P_line) reduce traditional energy consumption and the Environmental costs of bringing, the electric energy that transmission line of electricity fails to send is not abandonedFall, but utilize the remaining ability to transmit electricity of transmission line of electricity that this part electric energy is sent rush hour at generating low ebb or load, itsComputing formula is:

E(P_line)＝(r_c+r_e)×G_s(P_line)×T_s(8)

Wherein: r_cFor consuming traditional energy fuel used to generate electricity cost;

r_eFor its Environmental costs of bringing;

⑤C(P_line)

C(P_line) be transmission line construction cost, ask method as follows:

C(P_line)＝r_l×l×P_line(9)

Wherein: r_lFor unit length transmission line construction cost;

L is transmission line length;

⑥SC(P_line)

SC(P_line) be energy-storage system construction cost, ask method as follows:

$SC\left(P_{line}\right)=(r_{sp}\×P_{\max s}(P_{line})+r_{se}\×E_s(P_{line}\left)\right)\×\frac{T_s}{T_d}---\left(10\right)$

Wherein: r_spFor energy-storage system unit power cost;

r_seFor energy-storage system unit energy cost;

T_dFor energy-storage system life cycle;

E_s(P_line) be energy storage system capacity, because energy-storage system cost is higher, configure jumbo energy-storage system unrealistic,Energy-storage system desired volume only need calculate stored electric energy every day, and gets its maximum, and its computational methods are as follows:

$E_s\left(P_{line}\right)=max\left(\underset{0}{\overset{T_{line}\left(N\right)}{\∫}}{P}_{sd}\right(t,N)dt-P_{line}\×T_{line}\left(N\right))---\left(11\right)$

Wherein: N is number of days, get 1,2,3 ..., 365;

P_sd(t, N) is N days photovoltaic plant group accumulation power curves;

T_line(N) be that N days photovoltaic plant group power outputs are higher than P_lineThe continuous output time;

(1) the optimal solution P of formula object function_lineBe and make the maximized transmission line capability of comprehensive income, by P_line(7) formula of determiningAnd (11) formula, i.e. required energy-storage system power and capacity.